In existing long term evolution (Long Term Evolution, LTE for short below) networks, random access includes contention-based random access and non-contention-based random access.
A specific procedure of contention-based random access is that: a UE selects a sequence from a random access sequence set and sends a random access preamble (Random Access Preamble, RAP for short below) on a physical random access channel (Physical Random Access CHannel, PRACH for short below) predefined by a base station (eNodeB, eNB for short below). Random access responses (Random Access Response, RAR for short below) corresponding to RAPs sent by using a same PRACH resource are transmitted on a same physical downlink shared channel (Physical Downlink Shared CHannel, PDSCH for short below) and the PDSCH is indicated by a physical downlink control channel (Physical Downlink Control Channel, PDCCH for short below) that masks cyclic redundancy check (Cyclic Redundancy Check, CRC for short below) with a random access radio network temporary identity (Random Access Radio Network Temporary Identity, RA-RNTI for short below). Therefore, after sending the RAP, the UE may detect a PDCCH in each subframe in an RAR window. When a PDCCH scrambled with an RA-RNTI corresponding to the PRACH is detected, the UE may continue to demodulate a media access control protocol data unit (Media Access Control Protocol Data Unit, MAC PDU for short below) borne on the PDSCH indicated by the PDCCH. If a MAC header of the MAC PDU includes a MAC subheader corresponding to an RAPID, it means that the MAC PDU includes an RAR for the UE, and a random access succeeds.
In the prior art, within a cell, for a same PRACH time and frequency resource, namely a same RAPID, an eNB returns only one RAR. When two or more UEs within the cell send a same PRACH, the UEs have a low success rate of random access.